POWER DEVELOPMENT AT NIAGARA. 629 



the body of the metal of which the carrying wire is composed, 

 instead of, as in the case of a direct current, flowing across the 

 whole cross-section of the wire in an even manner. This also is 

 less serious the lower the periodicity. In the case of a lightning 

 flash (which is an alternating-current discharge) the periodicity is 

 enormously high, and it is known that in its flow over wires it 

 travels almost entirely through the mere surface skin of the 

 metal. It may be mentioned here, as having possibly a very 

 important bearing on work such as that under discussion, that a 

 most remarkable claim has recently been brought forth that bi- 

 metallic wires, or wires of one metal coated with a different one 

 on the outside, give remarkably improved results for the conduc- 

 tion of alternating currents over the conductivities of the two 

 metals in the weights used, laid together as separate wires. 



The form decided on in which to construct the conveying lines 

 is that of a conduit or subway of large proportions. One which 

 has been already constructed for a length of half a mile is as fol- 

 lows : The walls are arched, and the width is greatest at about two 

 thirds of the height. The conductors are carried on insulated 

 brackets along the sides, spaced at intervals of thirty feet. The 

 subway is lined with concrete, and manholes at intervals allow of 

 access ; besides, there are small pieces of pipe let in at the bottoms 

 of the manhole ducts for the purpose of inserting such wires as 

 may from time to time be required to tap the line conductors. 

 The subway is five and a half feet high and three feet ten inches 

 wide. A track runs along it, and the line inspectors will make 

 their trips on an electrically propelled car ; heavy wire screens 

 the height of the subway, extending on both sides of the track, 

 protecting the occupants from any possible discharge from the 

 main conductors. 



The Cataract Construction Company expect to be able to de- 

 liver power in Buffalo at a cost per horse power, for twenty-four 

 hours a day yearly, greatly below the cost of steam power as 

 now produced in Buffalo with coal at one dollar and a half per 

 ton. The generators are expected to operate at five thousand 

 horse power each, with an efficiency of ninety-eight per cent on 

 the power delivered to them by the turbines, and there will be 

 only three and a half per cent drop of pressure in transmitting 

 at twenty thousand volts to the northern part of Buffalo. This 

 last appears wonderful when we consider that it is less than the 

 drop from the generators of an electric railway system to the 

 motors of cars within as short a distance as half a mile, quite 

 apart, moreover, from the extra losses in the latter case due to 

 imperfect trolley contacts. It is hoped also to transmit power 

 before long to the Erie Canal, on which at the close of last sea- 

 son there was an interesting development in the line of electrical 



